Foldable platform



Nov. 18, 1958 H. HEISLER 2,850,383

FOLDABLE PLATFORM Filed Feb. 28, 1956 4 Sheets-Sheet 1 W}; as; a9 RL U {K 4e v 91.2 L: 7

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ATTORNEYS.

Nov. 18, 1958 H. HEISLER 2,860,383

FOLDABLE PLATFORM Filed Feb. 28, 1956 4 Sheets-Sheet 2 ATTORNEYS.

Nov. 18,1958 H. HEISLER FOLDABLE PLATFORM 4 Sheets-Sheet 3 Filed Feb. 28, 1956 fi ll-w- 2e v2 29 ATTORNEYS.

I VENTOR.'

4 Sheets-Sheet 4 ATTORNEYS.

H HEISLER FOLDABLE PLATFORM Nov. 18, 1958 Flled Feb 28, 1956 from room to room with'ease 'andconvenience. merous commercial situations would'ma'kethe same type This invention relates to a foldableplatform, and more especially to a platform stageada'pted to-be folded into a compact unit to afford portability t-he'r'eof.

There are many instances wherein itisdesirable tohave -a portable platform, especially' in the form "of a stage.

For example, in schools, it is frequently advantageous to have available a platform or stagethat could be moved of structure desirable, as in holding conventionsfin merchandising promotions, etc. While portabilityis a' key feature in uses of such types, portability mustbe provided for in a convenient and ready manner if such stages or platforms are to find wide-spread acceptance. That is to say, the stage must have the characteristic of being easily set up, and to thereafter offer a firm and stable platform, and coupled therewith must have the feature of-quickly and easily collapsing the stage to put it in portablecondition.

It is, accordingly, an object of this invention to provide a portable stage or platform that hasthese advantages. Another object of the invention is to provide a foldable stage or platform that can be c'onveniently and easily folded into a compact unit for storage and portability, and

that can be similarlyunfolded to place it in a condition for use. Still another object is that of providing a stage comprising a plurality of platform sectionsthat 'can be extended to form a planar platform adapted to support a number of people, etc. thereon, and alternatively being adapted to be folded into contiguous parallel planes that occupy a very small space, and wherein certain structural members of the stage serve to clamp and hold the platform sections in folded relation.

A further object of this invention is to provide a stage having a planar platform supported at an elevatedposition above a floor or other support surface, and in which the platform comprises a plurality of platform sections hingedly secured together and supported on rollers'that ride in support channels, whereby'the platform is folded or collapsed simply by pushing'the outer platform sections inwardly, which groups the sections together in contiguous planar relation-the support channels being mounted on legs and being inwardly pivotal whenthe platform sections are folded so as to extend alongside thereof,

means being provided in the structure to clampthe support channels and legs thereof in such folded condition to lock the folded platform sections in grouped condition.

Yet a further object is in providing a foldableyportable stage of the character described wherein intermediate support legs are automatically lowered into platform-supporting position when the platform sections are unfolded, and are also automatically retracted when the platform sections are folded together. Still a further object is to provide in a foldable' stage of the character described, safety lock devices of novel design and construction which serve to rigidly interlock the foldable platform sections with their support channels when thest'age'is unfolded. Additional objects and advantages willbecome apparent as thespecification develops.

An embodiment of the invention is'illustrated in the accompanying drawings, in which- Figure 1 is a perspective view-of afoldablestage embodying the invention shown in unfolded'positionor a United States PatentO condition of use; Figure 2 is a perspective view of the tially folded condition; Figure 3 isa perspective view of the stage showing the same in folded condition wherein it is readily portable; Figure 4 is abroken plan sectional view showing one of the support channel members in extended condition and the others in folded condition, but with the platform sections removed; Figure 5 is a bottom plan view of the stage showing the same in a condition of use; Figure 6 isa longitudinal sectional view taken along the line 66 of Figure 5; Figure 7 is a side View in elevation of the platform sections shown in extended or unfolded position; Figure 8 is a perspective view of one of the center hinges; Figure 9 is a broken longitudinal sectional view showing one of the safety locks in locked condition, the section being taken along the line 99 of Figure 11; Figure 10 is a sectional view similar to Figure 9, but showing the safety lock in unlocked position; Figure 11 is a vertical sectional view taken along the line 1111 of Figure 9; Figure 12 is a vertical sectional view simillar to that of Figure 11, but corresponding to the showing of Figure 10 so as to illustrate one of the locking devices in unlocked condition; Figure 13 is a broken perspective view of the underside of the stage, showing in detail the safety lock arrangements illustrated in Figures 9 through 12; Figure 14 is avertical sectional view taken-along the line 14-14 of Figure 15; and Figure 15 is a vertical sectional view taken along the line 15-45 of Figure 14.

In describing the invention, referencewill first be made to Figures 1 through 3 in particular since each of these figures is aperspective view showing the structure in its mostcomplete form, and showing also the various positions in which it can be placed. The stage is designated generally with the numeral 20, and comprises a platform 21 composed of aplurality of foldable platform sections-there being four in number in the illustration given, and foridentification, these are designated with the numerals 22 through'ZS.

ln'extended position as shown in Figure l, the platform sections are supported by means of four channels or channel supports that are designated with the numerals 26 through 29. The support channels are each provided at the outer end thereof with a leg, and the legs are designated with'the numerals 30 through 33. At their inner end, the legs are higedly secured to center leg members 34 and35-the support channels 26 and 27 being secured to the leg 34, while the channels 28 and 29 are secured to the leg 35. The hinge connection for the support channels is afforded in partby webs 36, 37, 38 and 39, each being secured, respectively, to the channels 26 through 29, and in turn being secured to the center legs 34 and 35 by hinge members 40.

It is clear from Figures 1 through 3 that the support channels 26 and 27 are adapted to be extended in alignment with each other, as are the'channels 28 and 29, when the foldable platform sections are unfolded into a planar position. These channels are also adapted to be folded into parallel alignment with each other, as shown in Figure 3, when the platform sections are folded into contiguous relation so as to provide a compact unit that is readily portable. Preferably, the support channels, and more especially the outer legs 30 through 33 of the stage structure, are reinforced by longitudinally extending reinforcing-members 41 through 44 which are spaced below and extend in parallel alignment with the respective channels 26 through 29. Furthersupport is given to the sides of the stage by connecting the various longitudinal reinforcingmembers 41 through to hinge arms 45 through 48, respectively, which are conventional andare formed in two parts'pivotally'ioined together at their centersthe'opposite ends of the-hinge arms 45 and 47 being secured to a transverse center support channel 49, and similarly, the inner ends of the hinge arms 46 and 48 being connected to a center transverse support channel 50.

The transverse support channels 49 and 50 which are spaced apart and are equidistant from the center transverse axis of the platform, have castor plates 51 and 52 rigidly secured thereto adjacent their opposite ends, and these plates adjacent the outer edges of the channels are bent upwardly and outwardly to provide platform elements having castors 53 mounted thereon. As is most apparent from Figures 3, 15 and 14 of the drawings, the center leg supports 34 and 35 do not normally engage a floor or other support surface upon which the stage is positioned, as do the outer legs 30 through 33, and instead the castors 53 are the floor-engaging members at the center of the stage.

It is seen most clearly in Figures 3, 5, 14 and 15 that spaced apart keeper members 54 and 55 extend across the channels 49 and 50 in parallel relation with the longitudinal axis of the stage, and are rigidly secured to the transverse channels by any suitable means, such as by welding. The keeper members are turned upwardly at their outer ends to provide clamp openings 56 into which the ends of the legs 30 through 33 are inserted when the stage is in folded condition, as shown in Figure 3. These keeper members then serve to retain the longitudinal support channels 26 through 29 in clamped relation with respect to the folded platform sections so as to prevent the stage from unfolding inadvertently.

As is shown most clearly in Figures 5, 6 and 13, the foldable platform sections 22 through 25 are each provided with a perimetric frame on the underside thereof, and for identification the perimetric frames (which are in the form of U-shaped channels) are designated with the numerals 22a through 25a. The platform sections 22 and 23 are hingedly secured together along the contiguous traverse edges thereof by means of generally conventional hinges 57, as' are the sections 24 and 25. The hinges, as is most apparent from Figure 6, are rigidly secured to the perimetric frames of the respective platform sections. The center sections 23 and 24 are hingedly secured together by hinge members 58 that are illustrated most clearly in Figure 8. I

These hinges have plates 59 and 60 which are rigidly secured, respectively, to the perimetric frames 23a and 24a of the corresponding platform sections, and plates 61 and 62 which are rigidly secured to a guide bar 63 that projects outwardly beyond the edges of the perimetric frames and, as is shown in Figures 15 and 14, extends into a vertical guide channel 64 and is slidable longitudinally therethrough. It will be appreciated that another such guide bar'63 at the opposite side of the sections 23 and 24 extends into a similar channel and is slidable therethrough. The channels 64 are oriented centrally with respect to the center legs 34 and 35 and are rigidly secured thereto. As is most apparent from Figures 4 and 15, the channels 64 are defined by two L-shaped members-one leg of each being rigidly secured to the center legs, while the other leg or web of each L-shaped member extends inwardly therefrom, and the respective legs of these members are spaced apart so as to form a channel through which the guide plate 63 is slidable.

It will be noted most clearly in Figures 14 and 15 that all of the support channels 26 through 29 are substantially rectangular in shape, and define longitudinally extending guide channels therein. The support channels are not completely closed, however, for each has formed along the inner wall thereof a slot that extends for its complete length. In Figures 11 through 13, the guide channels there illustrated are designated with the numeral 65, and the slot therealong is designated with the numeral 66. Rotatable within the substantially closed guide channels 65 are rollers which are designated with the numerals 67, 68, 69 and 70. It will be appreciated that two such rollers are provided for each platform section, one on each side thereof, and the rollers are connected to the platform sections by means of shafts or axles 71 through 74 that extend through the slots 66 and are secured at one end to the rollers and at the other end to the respective platform sections.

If reference is made to Figure 2, it will be seen that the various rollers guide the hinged movements of the platform sections 22 through 25 as those sections are folded into contiguous relation, as seen in Figure 3, and extended position, which is seen in Figure 1. The rollers are mounted substantially at the center points of the platform sections so that when those sections are folded, a part of each extends upwardly from the support channels 26 through 29, and a substantially equal portion thereof extends downwardly therefrom.

Although excellent support is provided for the platform sections 22 through 25 by the longitudinal support channels and rollers carried therein, it is preferred to use intermediate support legs located along the longitudinal axis of the stage and along the mating surfaces of the platform sections 22 and 23 and 24 and 25, respectively. Such intermediate support legs are shown most clearly in Figure 5. The leg assemblies comprise mounting plates 75 and 76 secured, respectively, to platform sections 22 and 23, and are angularly oriented with respect thereto. The plate 75 carries a plurality of straps 77, and similarly, the plate 76 has straps 78. The straps are rigidly secured to the plates by welding or by any other suitable means, and define semi-cylindrical eyes or loops that receive, respectively, for pivotal movement therein rods 79 and 80, each of which has extending outwardly therefrom intermediate its ends support legs 81 and 82, respectively. The end portions of each of the rods 79 and 80 is bent laterally or outwardly so as to provide the respective legs 83 and 84 that in their direction of extension are parallel to the legs 81 and 82.

Referring now to Figure 1, it will be seen that the legs 83 and 84 are secured together by a collar 85. The rods 79 and 80 lie along lines that are angled at substantially 45 with respect to the contiguous surfaces of the sections 22 and 23, and these rods define together then an angle of substantially 90. When the platform sections are extended, as shown in Figure l, the legs 81 through 84 depend from the platform sections and are substantially normal thereto, and are adapted to engage a support floor or surfacethereby supporting the foldable platform sections intermediate the outer edges thereof. On the other hand, when the platform sections are moved toward a folded position, as shown in Figure 2, the coupling or collar 85 extending between the legs 83 and 84 and locking them in adjacent parallel relation causes these legs to turn upwardly toward the mating edges of the respective sections 22-23 and 24 25 because of the force imposed thereon during such folding movement, whence the rods 79 and 80 rotate within the straps to permit such turning movement. This movement of the legs is automatic, and when the platform sections are folded together, they pivot so as to permit and accommodate the folding of the sections; and when those sections are unfolded or moved outwardly. the legs swing downwardly into a depending, supporting position for the platform sections.

It will be clear from an inspection of Figure 5 that a similar intermediate leg assembly is provided for the platform sections 24 and 25, and since this assembly is identical with the one just described, no further description thereof will be set out. For purposes of distinguishing this assembly from the one just described, the same reference numerals are employed except that the suffix "a has been added to each numeral.

The platform sections 22 through 25 are locked in extended position by a safety lock arrangement that forms an interconnection between eacli'iplatform section and the channel supports. Thefisaftety lock devieesxare shown 'best in Figures 9 "through 13', and 'refereiice will now be made to 'those 'figures in:particular '-in*describing' the structure. First, howeverpit'=111ayl::e*\ vellto mention that it is'preferred to use aplurality :of locking devices "for each -of-the platform"sections; and in the illustration given, four 'locks areused *for eachplatform sectiontwo on each side thereof;

Figure 13,whi'ch is a perspectiveview"of a portion of the underside ofthe stage with the platform sections extended, is the clearest over-all illustration of-the locking devices and actuating-means therefor. There shown=are portions of the platform sections 22 and 23 'togetherwith their perimetric frames" 22a and 23a, the support channel 29 and apart of the reinforcing flange 32. It will be apparent that when the platform sections areextended, the longitudinal members-of the perimetricframes 22a and 23a extend in parallel relation with' thesupport channel 29, and these frame portions have spaced apart openings therein ofoblong' configuration, and'since they are all identical, each is'designate'd with the numeral 86. The openings 86 are centrally aligned with' the slot 66 and the longitudinal axis of each '-'opening extends therealong.

Secured to the platform sections inward-1y of each opening 86 is a generally U-shaped"support' bracket87 having its base secured to the platform -section by screws 88, andhavingflang'es orlegs 89'and 90-depending therefrom. The dependinglegs are provided with aligned apertures therein that slidably receive arod'91, the inner end of which extends*beyondthe leg 89 and is provided with-a stop washer' 92 that providesa'seat for a coil spring93, the other end of which -seats'against the leg 39. The rod-91 atits other end extends between the leg 90 through theopening 86 and'to a position adjacent the slot66 in the-support channels. That end of the rod readily carries a lock member 94 that isof generally the same size and' 'shape as the opening 86, but is slightly smaller dimensionally than suchopening so as to readily pass therethrough, as is shown in Figures 10 and 12.

interposed between the leg 90 and lock member 94 in rigid relation with the rod 91 is a cam follower95 that carries a .spaced'distance below the rod 91 a cam rider or pin 96. The'pin 96 extendsinwar'dly through an opening 97 formed in"alink 98 that lies-within the longitudinal frame portions of the "perimetric frames of the platform sections. As is seen clearly in Figure 13, a plurality of links 98 are provided, and the links'are interconnected at their ends by means of pivot posts.

It willbe' apparent from Figure '13 also that the openings 97 are enlarged longitudinally along the links 98, and are of much greater dimension than the pins 96. The links 98 are free to move longitudinally with respect to the channel supports and longitudinal frame portions of the platform sections, and insuch movement and depending upon the direction thereof, either one edge or the .otherof' the openin'gs"'97 is brought into engagement with the pins 96. Since the rods 91 are rotatably supported'in thelegs of the U-shaped brackets, such longitudinal movement 'of" the links 98 through the interconnection of the openings 97 and pins 96 will cause the cam followers 95 to" swing about the longitudinal axis of the respective rods 91 and thereby pivot those rods, with the result that the lock members are swung from the horizontal release position (shown in Figures 10 and 12) to thevertical lockposition (shown in Figures 9 and 11).

Longitudinal movement of the links 98 is provided through a crank assembly 100 that comprises a crank arm 191 pinned to a cylinder 102 rotatably supported beneath the platform sections 22 and 25 in straps 103 secured thereto. The cylinder 102 has a rigid interconnection with a crank link 104 pivotally connected abiits other end rto 'a 'crankglink 105,'that at "its other end*is"pivotally connected to one of the longitudinally extending lock links 98. It will'be apparent that if the crank'arm 101is movedin a counter-clockwise direction, as viewed in Figure 13, the lock links 98 will be moved toward-the -right,'whereby those links will pivot the cam followers'95-and rods 91 in'acounter-clockwise direction to'rotate the lock'members "94 from the lock position -shown in'- Figures 9'and 11, to the release position shown in Figures 10 and 12. At such time, the crank arm 101 will be .moved upwardly from the position shown in Figure 13, and may then be pivoted outwardly about the lockingpin securing it to the cylinder 102 so that it lies along the undersurface of theplatform sections, and will not then interfere with the folding of those platform sections.

When in the unlock=position, as shown in Figures 10 and 12, the spring-93-is effective tomove the rod 91 inwardly, whereby the lock member 94 thereof lies substantially withinthe opening'97. In order-then that the 'lo'ck members are conditioned to rotate into a vertical position, as shown in Figures9 and 11, it is necessary that=the lockmembers be' moved to a position within the 'channel 65 in the channel support members. This is accomplished by bending portions of the lock links 98 outwardly, as is most apparent from Figure 13, so as to form cams designated with the numeral 106. Each cam "106 has an inclined forward cam surface 107, an inclined rear cam'surface 103-those surfaces being inclined outwardly and converging toward each otherand a flat'cam surface 109 interposed therebetween.

Whenthe crank assembly is moved to the position shown'in Figure 13, the lock links 98 are moved towar the left the same figure, whereby the inclined cam -sur faces"107 bear against the cam followers 95 to urge 'them outwardly against the biasing action of the coil springs 93. Such movement of the cam followers causes 'the -lock members-94 to enter the channels 65 inthe channel. support members. The-lock members 94 are then free to-rotate and, as has-been explained, rotational -mov' em'ent thereof about the axes of the rods 91 is ac- -'complishedby engagement of the cam follower riders or pins96 with the rear abutment edge of the openings 97'in'the lock links. Upon movement of the crank assembly-in an opposite direction, the link members 93 move toward the right in Figure 13, whereby the cam followers 95 ride down on the cams 106 to permit the coil sprin'gs"93 to urge the respective rods 91 and lock members 94 toward the position shown in Figures 10 and 12. With the same movement, the forward edge of the -openings97 engages the cam pins 96 to force it rear- -wardly, whereby the rods'91 are rotated to pivot the -lock members 94 into the horizontal unlock position shown in Figures 10 and 12. It will be noted in Figure 13 that the lock links 98 are pivotally interconnected by offsetting one end of a link, whereby the cams 106 of each linklie in the same plane.

In use of the stage-assume first the extended position thereof shown in Figure 1, and that it is desired to collapse the stage into the folded character depicted in -Figure-3. At this time, the safety lock members will be in the position shown in Figures 9, 11 and 13. The

first step in folding the stage is to swing the crank arms 101 from the downward lock position to an upward position of release. Ordinarily, four crank assemblies will be-provided -one on eachcorner of the stage. The coil springs'93 will then move the lock members 94 inwardly to release the platform sections from the support channels therefor.

Next, the workman positions himself along the outer free edge of either the section 22 or 25 and pushes inwardly on that edge. The inwardly directed force there- -against will cause the platform section against which it is" exerted and the one adjacent thereto-assume sec- 7 tions 25 and 24'to move through the partially folded position shown in Figure 2, and into the completely folded position illustrated in Figure 3. Next, the lever locks 46 and 48 are released, which permits the support channel 27 to be swung inwardly and into contiguous relation with the platform section 25. Next, support channel 29 is swung inwardly against the support channel 26; and these channels, the locks secured thereto, and the longitudinal support members 42 and 44 are locked in the position shown in Figure 3 by inserting the ends of the legs 31 and 33 into the keepers 54 and 55. The same procedure is followed to fold the sections 22 and 23 and the associated channel supports 26 and 28. The stage is then in the position shown in Figure 3.

During this operation, the intermediate support legs 81, 82, 83 and 84, and the similar intermediate legs adjacent the other end of the structure, fold upwardly automatically so that no particular attention need be directed toward their functioning, etc. On the other hand, those same legs move downwardly to supporting positions, as shown in Figure 1, when the platform sections are unfolded. This latter operation is accomplished by extending the support channels 26 through 29, locking the same in extended position through the hinge arms 45 through 48, and by thereafter drawing the platform sections 22 and 23 and 25 and 24 outwardly through the intermediate folded positions, as shown in Figure 2.

When the sections are extended, the crank arms 101 are swung downwardly and into the position shown in Figure 13 to effectuate an interlock between the platform sections and their support channels by means of the lock members 94. It will be apparent that keeper devices may be employed to lock the crank arms 101 in their down or up position, and as shown in Figure 13, the crank arm 101 may be provided with an opening 110 in the free end thereof for receiving the pin or book carried by the support flange 32 or, alternatively, a similar hook carried by the platform section 22. It is noted that the cylinder 102 is elongated and it, in conjunction with the arm 101, affords a triangular bracing at each corner of the stage, thereby giving added rigidity thereto.

While in the foregoing specification an embodiment of the invention has been described in considerable detail for purposes of making a complete disclosure thereof, it will be readily apparent to those skilled in the art that numerous changes may be made in those details without departing from the spirit and principles of the invention.

I claim:

1. In a platform structure of the character described, a pair of spaced apart support members, each of said support members comprising two segments carried adjacent the inner ends thereof for pivotal movement with respect to each other, a plurality of platform sections interposed between said spaced apart support members, said platform sections being hingedly secured to each other along the adjacent edges thereof, means for each of said platform sections carried by the respective support members and being movable longitudinally therealong for supporting the platform sections and being connected therewith at points intermediate the transverse edges thereof, said means being adapted to support said platform sections in planar relation when extended and to support the platform sections in substantially contiguous parallel planes when folded with portions of each section extending both above and below said sup-- port members, and means supporting said support segments to afford the aforesaid pivotal movement thereof inwardly along the planes of said platform sections when those sections are in folded position.

2. The structure of claim 1 in which certain of the adjacent platform sections have intermediate support legs, said support legs having portions thereof movably carried by such platform sections and additional portions engageable with a floor surface to support the sections,

.and in which means are PrQYiFkEQ Qr so movably carry-- 8 ing said leg portions on such "platform sections to permit said additional portions to be swung downwardly automatically into supporting position when the sections are extended and upwardly automatically during folding of the sections to permit such platform sections to be moved freely toward extended or folded portions.

3. The structure of claim 1 in which lock means are provided for interlocking said platform sections and said support members when the platform sections are in extended position said lock means comprising lock members provided respectively by said platform sections and support members.

4. In a foldable stage structure, a plurality of platform sections, said platform sections being hingedly secured together along the respective adjacent edges thereof so as to permit the sections to be selectively extended into planar relation or to be folded into contiguous vertical planes adjacent the center of the innermost platform sections, roller means carried by each platform section on each side thereof at substantially the center points of the respective side edges, and leg-equipped channel support members along each side of said platform sections, said roller means being carried by said channel support members for longitudinal movement therealong whereby the platform sections may be extended in planar relation between said supportchannels or folded therebetween with portions thereof extending both above and below the channel supports, said support channels having segments that are pivotal selectively between extended positions when the platform sections are extended so as to lie therealong and folded positions when the platform sections are folded so as to lie therealong.

5. The structure of claim 4 in which said channel support members are equipped with lock hinges for anchoring the same in extended positions.

6. The structure of claim 4 in which each of said platform sections is provided with safety lock means interconnecting the same with said channel support members when the platform sections are extended into planar relation, said safety lock means comprising lock members, and manually operable means for actuating said lock members carried by the platform sections and being engageable when actuated with said channel support members.

7. The structure of claim 6 in which said channel support members have longitudinally extending slots therein aligned with said lock members, and in which said lock members are rotatable and are adapted to be projected through such slots when in one position of rotation, means being provided for so projecting and rotating said lock members to interlockingly engage the same with said channel support members upon operation of said manual means.

8. The structure of claim 7 in which certain of said platform sections are equipped with intermediate legs, and in which means are provided for mounting said legs with respect to said sections to effectuate movement of the legs automatically between a depending position affording support for such platform sections when extended and a retracted position during folding thereof whereby the platform sections may be folded into contiguous parallel planes.

9. In a structure of the character described, a pair of platform sections pivotally secured together along contiguous edges thereof for folding movement between an extended planar relation and an adjacent parallel relation, and a leg assembly for said sections comprising a pair of rods pivotally carried respectively by said sections along the undersides thereof, said rods being oriented along lines intersecting each other adjacent the contiguous edges of said sections and forming substantially a angle, said rods at the point of intersection of such lines each being provided with a depending leg, and a'collar enclosing said legs and pivotally securing the same together in contiguous relation.

10. In a structure of the character described, a central transverse frame, support members extending laterally from said transverse frame at the ends thereof and being pivotally secured thereto for swinging movement into positions extending along the transverse frame, said support members being adapted to support a plurality of platform sections extensible into planar relation when the support members are extended laterally from said frame and selectively foldable into contiguous relation ad acent said central transverse frame, a leg carried by each of said support members, and keepers carried by said transverse frame and extending thereacross, said support members, when folded into positions lying along said transverse frame, having the legs thereof aligned with said keepers and being receivable thereby to lock the support members in such position.

11. In a structure of the character described having a support channel and a frame member extensible along said support channel, a safety lock arrangement for selectively interlocking said frame and support channel comprising a lock link extending along said frame, means for moving said lock link longitudinally between selected posltions, said lock link having a cam, a cam follower cooperative with said cam, a lock member structurally connected with said cam follower, said frame having an opening therein through which said lock member is movable, said channel having a recess therein aligned with said opening and through which said lock member is movable, and means biasing said lock member toward a position remote from said channel, said cam being operative upon movement of said lock link in one direction to urge said cam follower outwardly to move said lock member through said opening and recess and to pivot said cam follower to rotate said lock member into interlocking engagement with said channel.

12. The structure of claim 11 in which said means for moving said lock link longitudinally comprises a crank arm, and link means interconnecting said lock link and crank arm.

13. In a foldable platform structure, a pair of platform sections hingedly connected along adjacent edges thereof for movement between a substantially horizontal planar condition and a folded condition in which the sections are positioned in facing relation, a leg assembly for said sec tions comprising a pair of rods pivotally carried respectively by said sections along the undersides thereof, said rods being located along angularly oriented lines intersecting each other adjacent the aforesaid edges of said sections, each of said rods at the point of'intersection of such lines being provided with a depending leg defining a substantially parallel relationship therebetween, and a collar pivotally connected with each of said depending legs to couple the same and effect swinging movement of said leg assembly when said platform sections are moved between the extended and folded conditions thereof.

14. In a foldable platform structure of the character described, a pair of longitudinally extending supports normally positioned in spaced apart, substantially parallel relation, a pair of platform sections interposed between said support members and being hingedly connected along the adjacent edges thereof for movement between an extended, generally planar position and a folded position with the sections located in facing relation, means for mounting said sections on said supports to afford such movement of the sections between the folded and extended positions thereof, a leg assembly for said sections comprising a pair of rods pivotally carried respectively by said sections along the undersides thereof, said rods being located along angularly oriented lines intersecting each other adjacent the aforesaid edges of said sections, each of said rods at the point of intersection of such lines being provided with a depending leg defining a substantially parallel relationship therebetween, and a collar pivotally connected with each of said depending legs to couple the same and effect swinging movement of said leg assembly when said platform sections are moved between the extended and folded conditions thereof.

15. The structure of claim 14 in which a transversely extending frame is provided, and in which said supports are pivotally secured to said frame for swinging movement between the aforesaid spaced apart parallel relation thereof when said platform sections are extended and a retract-ed position extending along said frame when said sections are folded.

16. The structure of claim 15 in which said frame is equipped with a keeper, and in which said supports are interlockingly engageable with said keeper when in the retracted position thereof.

17. In a foldable platform structure, a generally rectangular frame, a plurality of support members extending laterally from said frame adjacent the corners thereof and being oriented relative to each other to define a relationship of axial alignment with one support member and parallel alignment with another, a plurality of platform sections hingedly connected along the respectively adjacent edges thereof so as to afford selective movement of the sections between an extended generally horizontal relation and a folded relation in which the sections define facing generally vertical planes, means carried by each of said sections in engagement with the respective support members and movable longitudinally therealong to support said sections in the extended and folded positions thereof and for movement therebetween, and guide means having coactive elements thereof provided by said frame and the platform sections adjacent thereto for constraining such adjacent sections for positively locating such adjacent sections with respect to said frame.

18. The structure of claim 17 in which said guide means comprises a vertically oriented channel carried by said frame and a bar carried by the aforesaid adjacent sections along the hingedly connected edges thereof, said bar having a portion thereof extending into said channel for sliding movement therealong.

19. The structure of claim '17 in which each of said support members is pivotally connected to said frame for swinging movement into a retracted position extending along the frame when said platform sections are in the folded position thereof.

20. The structure of claim 17 in which selectively operable lock means are provided having interconnecting elements thereof carried respectively by said support members and platform sections for anchoring said sections in the extended position thereof relative to said support members.

21. The structure of claim 17 in which at least certain of the adjacent platform sections are equipped with a leg assembly therefor, said leg assembly comprising a pair of rods pivotally carried respectively by said certain adjacent sections along the undersides thereof, said rods being oriented along lines angularly intersecting each other adjacent the hingedly connected edges of said certain platform sections, each of said rods at the point of intersection of such lines being provided with a depending leg, and a collar pivotally connected with each of said depending legs to couple the same and effect swinging movement of said leg assembly when said platform sections are moved between the extended and folded positions thereof.

References Cited in the file of this patent UNITED STATES PATENTS 

